Measuring device for high-voltag networks



Fb.1-5,19z7. 1 mar/,912

H. KAFKA ET Al. I MEASURING DEVICE FOR HIGH/VOLTAGE NETWORKS Filed Nov.30, 1923 wur L1 ma@ @AN Patented F eb.` -15, 1927.

. UNITED STATES HEINRICH `IKAFKA, OF BERLIN-LICHTERFELDEWES'F, ANDSIEGFRIED KLEIN, OIE` COPENICK, NEAR BERLIN, GERMANY, ASSIGNORS T0SIEMENS & HALSKE, .AK-4

PATENT OFFICE.

TIENGESELLSCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY, A CORPORA- TIONOF GERMANY.

MEASURING DEVICE FOR HIGH-VOIJTAGE NETWORKS.

` Application filed November 30, 1 923, Serial No. 677,747. and inGermany November 30l 1922.

Our invention relates to measuring devicesfor high voltage networks andmore particularly to voltage and output measurements in dou'ble mainsand three-phase current mains.

According to our invention special cascade connections of condensers orother devices already existing on the lines and acting like suchcondensers connected in series, for in stance bushings, are utilizedvfor connection with the measuring devices. Each of these condenserdevices yis connected at one end with one of the mains and at the other4end with a constant potential, such as a grounded conductor. In thecondensers suitable intermediate armatures are selected and connectedWith the measuring device, which absorbs the electric current. The.measuring device may either be directly connected with theseintermediate armatures or indirectly by means of measuring transformers,which are connected as current transformers. `In three-phase networks avery convenient measurement of output is possible besides the voltagemeasurement. Preferably a dynamometric instrument is employed in thiscase. f v

Some embodiments of our invention are illustrated by way of example inthe drawing, which represents in Fig. 1 a connection for voltagemeasurement, in which the measuring device is connected with the highvoltage mains,

Fig. 2 a connection forvoltage. measurements, in which the measuringdevice is connected with cascade connections of condensers branching offthe mains,

Fig. 3 a connection Yfor power` measurement in three-phase networks bythe aid of two bushings and a current transformer in one of the mains,Y,

Fig'. 4 a connection for power measurement in three-phase networks inwhich con; densers connected in cascade and a current transformer in oneofA the mains serve for connecting the measuring device and F ig. 5 aconnection for simultaneously measuring the wattless and the effectivecurrent in a'three-phase network.

Similar parts are indicated by similar reference characters in all 'thefigures of the drawing.

Referring to Fig. 1, 4 and 41 are two bushings for the high voltagemains 1 and 2.

Their outer armatures 5 and 5 are connected with the conductor 8 whichis earthed at 9. The intermediate armatures 6 and 6 are connected withone end respectively of the primary coils 10 and 10a of thel measuringtransformers 10 and 10', the other ends of thesecoils being connectedwith the conductor 8 at 8. AWith the secondary coils 10b and 10' of thetransformers 10 and 10 is connected the voltmeter 13 across thechange-over switches 11 and 12. By turning the change-over switches 1land 12 either on vwith the secondary coil 10b of the transformer.

Referring to Fig. 3, Which illustrates a connection for power measuringin threephase networks, the primary Winding 27 of a current transformer20 is arranged in the main 1, the secondary winding 28 of thetransformer feeding the current Winding 19 of the dynamometricinstrument. In the mains 2 and 3 the outer armatures 5 and 5 of thebushings 4 and 4 are connected with the conductor 8 which is earthed atits other end at 9. The intermediate armatures 6 and 6 are connectedwith the voltage coil 18 of themeasuring device 13.

Referring to Fig. 4, 1, 2 and 3 are threephase mains. In the main 1 isarranged the primary coil 27 of a current transformer 20, the secondarycoil 28 of which is connected with the two terminals of the current coil19 of the dynamometric instrument 13. The condenser series groups 16, 16and 16 are connected at one of 'their ends with the mains 1, 2 and 3respectively and their other ends are connected with they conductor 8earthed at 9. Those intermediate armatures which are nearest to theconstant ground potential are indicated by 22', 22, and 22. Thearmatures 22 and 22 are connected by the vconductor 21. The armature 22is connected with one terminal of the primary coill 10 of a measuringtransformer 10 by a' mains. This result is attained in Fig. 4 byconnecting the voltage coil of the cross-coil instrument, the current ofwhich should be proportional to the neutral point Voltage, for instanceof the main 1, preferably across a measuring transformer, which isconnected not only with intermediate armatures of the bushings of thismain alone, but with the intermediate armatures of all three bushingslocated nearest to the constant potential, these intermediatearmatures,A being lconnected together in series with the primary of thetransformer as shown. It follows 'from`| this 'connection that thecharging current of this-intermediate armature consumed by the coil isproportional tothe voltages between vtwo mains which remain unchangedwhen an earth leakage occursin one main,.and therefore is proportionalto the neutral poi-nt voltage.

A similar deliberation underlies the coinbination illustrated in Fig. 5of a power connection and a wattless connection, which] are bothindependent from earthleakages and similar potential displacements.Referring to this figure 1,2l and 3 are the mains of the network 4, 4and 4 bushings for the mains, the outer armaturesof which 5, 5 and 5 areearthed at 9 by -means of the conductors 8, 8 and 8. In the bushings theintermediate armatures 23, 23 and 23" next to the y outer armatures 5, 5and 5 are connected with the conductor 26 respectively at 25, 25 and 25across the primary coils 24a, 24' and 24 f1 of theinstrumenttransformers 24, 24 and 24. The secondaryicoil 24b of thetransformer 24 is connected with the voltage coil 18 of a wattlesscurrent meter 13. Its current coil 19 is fed by the secondary coil 28 ofthe current transformer 20. the

primary coil 27 of which is arranged in the' main 1. The current coil 19is connected in series withthe current coil 19 of the neiaeia ypowercurrent meter 13 The voltage coil 18 of the last mentioned measuringinstrument isA connected in parallel with both secondary coils 24b -and24b of the measuring transformers 24 and 24 one of\ the secondary coils,lin this case 24, being connected with reversed terminals.The-connectionsillustrated in the Figures 4 and 5 are particularlysuit-able for measurements in symmetrically loaded three-phase currentnetworks.

What We claim as our invention and desire to secure by Letters Patentis 1. In high voltage networks having a plurality of mains, thecombination 0f a plurality` of devices having the effect of armatures ofcondensers connected in series, each of said devices connected with oneend to one of said mains, a conductor of 'constant' potential connectedto the other end of said condenser devices, a measurin device having twocoils, one of said coi s bein nected to intermediate armatures o saidcondenser devices, and a current transformer having a primary windingarran ed in one of said mains, and having a secon ary winding connectedto the second coil of said measuring device.

2. ln high voltage networks having a plurality of mains, the combinationof a plurality of devices having the edect of armatures of condensersconnected in series, each of ,said devices beingconnected with`one endto one of said mains, la conductor of constant potential connected tothe other end of said 4condenser devices, a plurality of conductorsconnecting together suoli intermediate armatures of said condenserdevices as are located nearest to that connected to the 'conductor ofconstant' potential, a measuring device having two coils, one of saidcoils being connected to said conductors connectin together saidintermediate armatures o said condenser devices and a currenttransformer having a primary winding arran ed in one of said mains, andhaving a secon ary winding connected to the second ,coil of saidmeasuring device. i

3. In'higliv voltage networks having a plurality of mains, thecombination ofa plurality of devices having the effect of armatures ofcondensers,v connected in series, each of said devices being connectedwith one end to one of said mains, a conductor of constant potentialconnected to the other end of said condenser devices, a plurality ofconductors connecting together such intermediate arma- :ture's of saidcondenser devices as are located nearestA to that connected to theconductor fof constant potential, a measuring device having two coils,one of said coils being connected to two of said conductors connectingof said mains, and a secondary Winding conthird of said conductorsconnecting tovether nected to the second coil of said measuring saidxintermediate armatures of sai condevlce, and a second measurlng devlcehav denser devlces.

ing two cois,one of said coils being -con- In testimony whereof We aiixour signnnected to said secondary Winding of said tures. w transformer,the second coil of said second HEINRICH KAFKA.-

measuring device being connected to the SIEGFRIED KLEIN

